(fallen london stamps by instead of doing work this morning I am thinking about the nebulous literary phenomenon where many isekai settings end up feeling like they're just an elaborate backdrop for the isekai'ed main character rather than real worlds in their own right
(the context for this is that I am grouchy because I read through a webnovel on a whim yesterday and was Displeased with it because it felt too much like they were willy-nilly killing off various characters in the otherworld before their arcs could be properly explored, for the sake of Letting The Earth MCs Have Awesome And/Or Traumatizing Moments)
also I think a personal thing for me is that I tend to get invested in settings far more than I get invested in individual characters. my questions when engaging with media are almost always "but what's over in that part of the world?" "how does this aspect of the world work?" "how are these events going to affect the world down the road?" if your setting is just set dressing and you keep veering away from (what I consider) the interesting questions in favor of making the MC have a bunch of cool moments, I will get frustrated and leave
(it does not help that a lot of isekai main characters are kind of generic beyond their common premise of "what if an Earth human got dropped into a fantasy world," and it's less the character that you're engaged with so much as their premise. and looping back to the original complaint that started all this, when all the potentially engaging characters get killed off to feed this premise and the MC isn't really engaging enough on their own, I just go "oh, whoops, just realized that I actually need more than the premise for this to work!")